"There is nothing that you have said or done that is acceptable to me in the least. You're a traitor to this country and a disgrace to your office. And it's my duty to see that you're brought to justice for what you've done. Is there anything else, Charles?"

By Day 6, Pierce was regularly spending time with Martha, but by Day 7, he was no longer with her and was residing in Washington, D.C. He was called upon by Bill Buchanan to inform Olivia Taylor of the attack on her father, at which point he stayed to look after her at her request. He was, however, influential in bringing her to justice for the murder of Jonas Hodges.

During Day 1, a threat was discovered on the life of SenatorDavid Palmer, the first African-American with a shot at the White House. Pierce was put in charge of the Secret Service detail to protect Palmer, and arrived at his hotel at around 1:45am to inform the Palmers of the threat. He introduced himself to Sherry Palmer, but found that the Senator was not in his room so informed the agents and had them check the GPS for vehicles. ("1:00am-2:00am")

Pierce and his unit then questioned Palmer's staff, and he explained to Sherry that the threat was serious. He had to stop Keith Palmer from leaving the suite, explaining that the threat was taken to be against the whole family. Later, Palmer was located at Hotel Rosslyn and the agents brought him back to the suite. Once he returned, Pierce had a word with Palmer to explain the seriousness of the threat. He suggested some changes to his schedule, and expressed a desire to cancel his breakfast speech, but Palmer was adamant that it stayed. ("2:00am-3:00am", "3:00am-4:00am")

Palmer then arranged a meeting with Maureen Kingsley in the 3rd floor conference room of the hotel, so Pierce supervised the searching of her before the meet before leaving them in private. Later, shortly after 6am, Pierce accompanied Palmer in his motorcade as they found Keith out jogging. Keith initially tried to run away, and Pierce had his agent attempt to bring him in, but Palmer had him called off as he wanted to speak to his son alone. They talked, and Palmer returned to the hotel. ("4:00am-5:00am", "6:00am-7:00am")

Shortly after 7am, Pierce prepared for the Senator's breakfast speech at Santa Clarita Power Plant. He was heading up security, and cleared a man claiming to be the photographer Martin Belkin. He continued working at the security checkpoint when Jack Bauer arrived, and Aaron searched his briefcase before clearing him through. Palmer was on his way up, and arrived soon after. Pierce then received a call from Tony Almeida at CTU Los Angeles, who told him that Jack Bauer had been compromised and could be a threat to the Senator.

Pierce tried to persuade Palmer to leave, but Palmer said he would lose the face time but needed to give his speech. Pierce then informed the rest of agents to find Bauer. Alan Hayes told him that Bauer had been spotted, so Pierce went to his position. However before he got there Bauer went for Hayes's weapon and Palmer had to be escorted from the building. ("7:00am-8:00am")

The Senator was then escorted into his car by Pierce and his team, and he told Berkin to stay with the Senator during the extraction. Pierce got into the front seat of Palmer's limousine as they drove back to his hotel, while Frank Simes dealt with Bauer. ("8:00am-9:00am")

At around 3pm, CTU sent photos of Alexis Drazen, Jovan Myovic, and Mishko Suba (three Serbian assassins) to Palmer's security detail. Aaron briefed all the staff at around 5 past, showing them the photos and asking them to let an agent know if they saw them. Elizabeth Nash recognized one of them as her boyfriend, so she was sent to CTU for questioning. ("3:00pm-4:00pm")

Nash agreed to a sting operation in Alexis Drazen's hotel room, and Pierce greeted Jack and the team when they arrived on the 12th floor. Pierce apologized for Jack's treatment by Secret Service that morning, and Jack introduced them to agents Nina Myers, Aleshire and Johnson. Pierce showed Jack Alexis's room, and also covered all the exits of the hotel. ("4:00pm-5:00pm")

During Day 2, Aaron was in charge of the Secret Service unit that protected President David Palmer. When a nuclear bomb went off in the Mojave Desert (originally supposed to be set off in Los Angeles), it became a priority to protect Palmer from any possible threats.

Aaron Pierce was put in charge of guarding President Palmer. When Palmer asked if he could talk to Pierce about the day's events, Pierce said he wasn't authorized to talk, but he could listen. Despite his best effort's to remain silent, Pierce offered his word to Palmer, and he realized Palmer shouldn't have been removed from office.

When Palmer needed to get in touch with Bauer, he asked Pierce to get a satellite phone for him. Pierce proved to be loyal when he got the phone, but when Mike Novick found out, he placed Pierce under arrest. As Pierce was being escorted out of the room, President Palmer apologized to him for getting him involved. Agent Pierce told him that he had nothing to be sorry for, addressing him as "Mister President".

When it was proven that the evidence implicating the countries was fabricated, President Palmer was reinstated back as the commander-in-chief. Palmer had the charges dropped against Pierce, and though Palmer refused for any of the Cabinet to resign, he fired Mike Novick, as he felt personally betrayed by him.

Throughout the day, Pierce protected the president and gave Sherry Palmer clearance to see Palmer. Later that day, Stephen Saunders contacted Bauer and asked for him to get him in contact with Palmer. Saunders told Palmer that he wouldn't release the vials of the virus, if Palmer would cooperate and follow his demands. He told Palmer that he would have a package waiting across the street for him.

Pierce went to get the package, but he had it scanned for any biological weapons, explosives, or any other threats that may of been placed in it. Pierce told Palmer the package was perfectly fine and Pierce revealed that inside the package was a non-traceable phone. The phone would be used for Palmer and Saunders' communications. Among the things Saunders demanded for was the phrase "the sky is falling" to be used in a press conference, the execution of Ryan Chappelle, and for Palmer to place information on Sylviaimports.com.

When the virus was released in the Chandler Plaza Hotel and a small outbreak started to occur throughout the city, Pierce told Palmer that Los Angeles was no longer safe and he needed to be transported back to Washington. When Palmer said he preferred to rermain in Los Angeles, Pierce said the Secret Service was invoking Section 32 and requiring him to comply. Palmer spoke to Pierce privately and asked as a personal favor to keep him in Los Angeles. Pierce reluctantly agreed to Palmer's terms, and protected him for the rest of the day.

During Day 4, Pierce served under President John Keeler. However, Mitch Anderson gained access to a Stealth fighter and he shot Air Force One down. Keeler survived the attack in critical condition, and Pierce was detailed to serve Keeler's Vice President, Charles Logan, who was sworn in as the new president, but he had difficulties making crucial decisions. One of Logan's closest advisors, Mike Novick, suggested for Logan to bring in Palmer to serve as an advisor. Agent Pierce was honored to be protecting Palmer again.

When CTU apprehended Mandy, who had been holding Tony Almeida hostage, she agreed to help them find Habib Marwan for full presidential immunity. Bill Buchanan and Michelle Dessler called Logan and Palmer, who both agreed to giving Mandy immunity. However, Agent Pierce revealed that Mandy was the same assassin who attempted to kill Palmer in Day 2. Despite the circumstances, Palmer decided it was best to give her immunity.

Eventually Aaron lost his patience, and threatened to let himself in Martha's room if Evelyn didn't open the door. Using his own key, he came in the room and looked for the First Lady. When he noticed she wasn't in the room, he asked Evelyn and threatened that if anything happened to her, she would be held responsible. Evelyn confessed that Martha went to one of the archive rooms to get a transcript of a conversation between her and David. When he went there, Aaron found Martha digging through files. He told her it was time to leave, and escorted her outside. Aaron then went to Walt Cummings and told him about Martha being in the archive rooms looking for a written transcript. ("Day 5: 9:00am-10:00am")

After Logan decided to send Martha to a rehabilitation clinic in Vermont, Aaron went with him to escort her outside. When Logan realized Martha had escaped through the bathroom window, Aaron quickly informed all the Secret Service agents to look for her. He then went outside to coordinate the search. ("Day 5: 11:00am-12:00pm")

Aaron and his men were searching for Martha in the stables. When he found her hiding, she pleaded him to protect her and assured him that someone was trying to keep her silent. At this point, Agent Steve and another agent arrived to take Martha. Although she asked Aaron to stop them, he only stepped aside and obeyed.

When Jack Bauer came to the presidential retreat to meet with Mike Novick, Logan had Bauer arrested and Novick placed under the watch of guards. When Pierce learned that Bauer was being detained, he asked one of his men why Bauer was there, why he was under arrest, and why he wasn't informed about it. The agent told him they had received orders from the President through Walt Cummings. Pierce decided to watch Bauer himself and learn why he met with Novick.

When Pierce went to transfer Jack out, he told him about Cummings involvement in the selling of Sentox VX nerve gas to terrorists and Palmer's assassination. Aaron then decided to let Bauer out and help him confront Cummings. After sending one of his agents out with a distraction, Aaron led Bauer into Logan's office. When Jack began assaulting Cummings, Logan demanded for Pierce to stop it, but he assured him he was doing it for his protection. After Bauer got the information out of Cummings, both he and Pierce offered to turn themselves in. Logan refused and asked for Pierce to get Walt out of his sight. ("Day 5: 12:00pm-1:00pm")

When Martha wanted to ride with the Suvarovs to the airport, Pierce decided to ride in the front of the limousine. Martha insisted that it wasn't necessary, while Aaron felt it would be best if he went along for the ride. Throughout the car ride, Pierce was asked by Martha if there was any changes to the motorcade route. Towards the end of the ride, Aaron was contacted by Bill Buchanan from CTU Los Angeles. He learned there was a possible threat to the motorcade and ordered for it to be turned around.

Vladimir Bierko's men realized the Secret Service learned about the possible threat, and they began attacking the motorcade. After launching an RPG that hit the Suvarov's limo, the terrorists began killing all of the surrounding agents. Aaron ended up getting knocked unconscious and the terrorists began to try to get into the limo. Aaron eventually woke up and opened the car door, he then shot Eric and another terrorist, saving Martha and the Suvarovs.

Martha was shakened up about the attack and she told Aaron that President Logan knew about the attack all along and didn't stop it. After they arrived back at the retreat, Martha asked for Evelyn to get Aaron for her. Aaron came into her room and Mike interrupted an emotional moment between them. Aaron told Mike nothing happened and he warned Aaron that nothing better happen.

Later that evening, President Logan and Vice PresidentGardner decided to evoke Martial law in Los Angeles, but call it a curfew in order to avoid getting permission from Congress. After Logan announced the curfew, Aaron was contacted by Wayne Palmer. Wayne told him he was on his way to Los Angeles and needed to see him.

When Aaron lost contact with Wayne, he informed one of his fellow agents that he was going to go out and try to look for him. Eventually Aaron was lead to a field and was told to put his gun down by an armed man. Aaron discovered that the man was Wayne, as people working for Christopher Henderson were trying to kill him. After handling Henderson's men, Aaron and Wayne headed back to the retreat.

Aaron learned from Wayne that there was a source inside the White House. The source happened to be Evelyn Martin, who was trading e-mails with David before his death. Evelyn revealed that she had evidence that proves who is behind everything that happened during the course of the day. Evelyn agreed to help Wayne expose this person, if he was able to help rescue her daughter Amy from Henderson.

While preparing to meet with Evelyn and Jack Bauer, Wayne and Aaron ran into Vice President Gardner. Gardner was shocked to see Wayne and he gave his condolences for Wayne's loss. After claiming that David was one of the greatest presidents, he asked why Wayne was here. Aaron revealed that Wayne had a memento from David that he wanted to give to him, as Aaron and David were close. Gardner then let them pass and later talked to Logan about Wayne's presence.

While Wayne and Jack worked on helping Evelyn, Aaron stayed at the retreat to keep everything in order. When Aaron learned that Logan put an out an arrest warrant for Jack Bauer, he called Jack and asked if President Logan was behind the day's events. Jack confirmed that Logan was the man behind David's death and the selling of the Sentox. Aaron told Jack that every law enforcement agency would be looking for him and in turn, Jack told Aaron to watch his back.

Mrs. Logan eventually became suspicious of her husband, as she had the feeling he was hiding something from her. She went to Aaron to ask him about it, and he told her to meet him outside. Martha went to meet with Aaron, but he was nowhere in sight. She found his cell phone and asked Charles about his location. President Logan told her that Agent Pierce was reassigned to Washington.

A little after 4am, it was discovered that Pierce was alive and being held captive by Logan in the presidential retreat. Logan offered to put everything behind him and have Pierce reassigned, but Pierce refused and accused Logan of being a disgrace to his office. After Graem Bauer told Logan that Pierce would possess a big threat, Logan ordered for Justin Adams to kill Pierce.

While Adams was preparing to kill Aaron, Martha discovered them and began to walk towards Agent Adams. Adams was distracted and Aaron hit him to the floor. Eventually Adams gained control of the situation and was about to kill Aaron, but Mrs. Logan picked up his gun and shot and killed Adams. Aaron put Agent Adams in the trunk of Adams' car and he asked Mrs. Logan to find Mike Novick and tell him about everything that has happened.

Once Mike realized what the president was responsible for, he agreed to help get Aaron to a safe location. Aaron said his good-byes to Mrs. Logan and got in the back seat of the car. While Mike and Aaron were bringing Adam's body to the fields, Mike got a call from Jack Bauer, who was looking for Aaron. Aaron informed Bauer that he could trust Mike, and Jack asked for their help in bringing Logan to justice.

Aaron informed Jack that Logan would be giving the eulogy at Palmer's funeral and would be leave momentarily, so they decided to bringing Mrs. Logan in on their plan. While Martha stalled her husband, Aaron helped get Jack access to the Secret Service building. With help from Chloe O'Brian at CTU, Jack was able to get one of the pilots come back to the Secret Service building. Jack decided to pose as the pilot and Aaron wished him luck as he left.

After giving Palmer's speech, Secret Service agents took Logan into custody. Though Jack failed in getting Logan to confess, that was only a diversion, as a conversation between Martha and Charles is what implicated him in Palmer's death and the selling of the Sentox.

After the events of Day 5, Aaron continued to become close with Martha Logan. Martha entered an institution to deal with the stress her husband caused, and Aaron often visited her. They eventually began a romantic relationship, and by the events of Day 6 they were living together.

At around 6:22pm, Aaron arrived home with fruit from Mel. Aaron greeted Martha, who was reading a book. When Martha began to get emotional, she received a phone call and she asked for Aaron to get it. Aaron was shocked when he learned that it was Former President Charles Logan calling. When Aaron handed Martha the phone, she quickly refused to speak to him any further and Aaron talked with Charles.

Charles claimed that Martha could help in an international situation, dealing with the Suvarovs. When Martha refused to visit with Charles, Aaron agreed to convince Martha to allow him to come. When Charles arrived at Martha's home, Aaron refused to shake Charles' hand and he lead him to Martha. Martha locked herself up in her bedroom, but Aaron was able to convince her to come out and speak with Logan.

Logan revealed that Consul Anatoly Markov was connected to the nuclear explosion that occurred in Valencia earlier in the day. The only way to get to Markov without starting a war with Russia, was if President Yuri Suvarov would cooperate with CTU Los Angeles. Martha agreed to talk to Anya Suvarov about it, but she was giving a speech in Russia. When Aaron suggested for Logan to wait outside, Charles chose to stay, which made Martha act more agitated.

When Martha was bringing a knife back to the kitchen, she stabbed Charles in the shoulder. Aaron called for a medic as Agent Shavers placed Martha into custody. When CTU came into contact with Anya, Aaron asked Martha if she was stable enough to talk. Martha insisted she was and talked to Anya about the situation at the Russian consulate. When Markov refused to turn himself in, Suvarov authorized the raiding of his consulate.

Bill Buchanan called on Aaron Pierce to pick up the President's estranged daughter, Olivia Taylor and bring her to the hospital where her father was undergoing surgery. Olivia was reluctant to leave since she was in the middle of a business meeting with Arthur Carr. She also noticed that Aaron's badge said he was retired and pointed that out to him. However, Aaron insisted and after Carr left, he explained to her that her father had been shot in the chest and that he was in the hospital. Bill later redirected Aaron to take Olivia to the White House.

While at the White House, Olivia became impatient and said that she wanted to see her father. Aaron told her that she had to remain there for the time being. When Benjamin Juma attacked the White House, Aaron protected Olivia. While everyone else was held hostage by Juma, Aaron and Olivia were hiding trying to alert the others outside the White House that Juma didn't have President Allison Taylor. Juma's men soon found them. As Olivia and Aaron ran down a hallway, he was shot in the shoulder but still managed to kill Juma's men. He then prompted Olivia to get to the window and send the signal before more guards arrived. He wrote the Morse code on her hand and sent her off. However, Udo and Juma's soldier found them and brought them with the other hostages.

When Bill Buchanan sacrificed himself to create a distraction, Jack shouted to Aaron to protect the President. Aaron ran towards her and secured her and Olivia, escorting them out of harm's way. After the Secret Service and FBI cleared the White House, he was tended by the medical staff. Olivia thanked him for saving her life and asked him why he had retired. When she asked him if it had something to do with what happened to Martha Logan, he refused to talk about it. He still accepted her thanks, and told her she could address him as "Aaron" (instead of "Agent Pierce"). ("Day 7: 8:00pm-9:00pm")

A few hours later, Olivia, the newly-appointed provisional Chief of Staff, saw Aaron who had just finished submitting his statement about what happened at the White House. She asked him if she could reinstate him as her head of security, because she could trust him. He initially declined, but eventually accepted her offer. A little after midnight, Olivia asked Aaron to drive her to Roosevelt Continental Hotel where she would meet someone, not telling Aaron it was reporter Ken Dellao. As they approached the room, Aaron told her he would have to check the room, but she refused to let him do so. He insisted, but she calmed him and told him to wait outside. About half an hour later, she came out and received a call from her mother who told her to return to the White House. He seemed suspicious of her actions while leaving the building with Olivia.

After 3:00am, Aaron went to Olivia and asked her about the document the President had asked her to draft. Olivia, angered at her mother's decision, revealed to Aaron that the document was a presidential pardon for Jonas Hodges. Aaron tried to calm her telling her that the President was doing what was necessary to protect the country, but Olivia was still angered since Hodges was responsible for her brother Roger's death.

At around 4:16am, Aaron led Martin Collier into Olivia's office. Although he didn't know that Olivia was scheming to have Hodges killed, he still looked suspiciously at Martin as he left. When Henry Taylor was transferred to the White House, he went into Olivia's office to inform her. Later, when Olivia found out about Hodges' death, she walked out of the Oval Office visibly distraught. Aaron approached her and asked if she was okay, and she told him she was.

He later called her while Olivia was meeting Martin Collier and told her she should be at The White House. She told him she was out an errand. When she came back she told him she needed to get a break from everything that had happened. She told him she was sorry she just left, and said it wouldn't happen again. Aaron agreed, and told her if it happened again, she would have to find another agent. Being suspicious, he called Ethan Kanin, and asked if the recorder in his former office still was functional. Ethan said yes, but that it needed his fingerprints to get access to it. Ethan asked what it was for, and Aaron told him he couldn't tell him over the phone. Ethan said he would be at the White House in half an hour.

Kanin arrived on schedule, and Aaron led him into the Chief of Staff's office. Olivia returned to find Kanin there. After Kanin departed, Aaron played dumb as to Ethan's reasons for being there. Aaron continued to serve as Olivia's personal body guard until he and Ethan confronted Olivia with the recording. Aaron guarded the room where Olivia told Henry and Allison Taylor about her actions, and Aaron was personally responsible for taking Olivia into federal custody.